This invention relates to the processing of image data, and more particularly to a system and method for producing high resolution gray scale image data representing an image.
The system and method of the present invention is especially useful in image processing systems wherein the images from documents, such as bank checks, are stored electronically in a computer system and the images may be subsequently retrieved for display or printing.
One such system is disclosed in commonly owned copending U.S. application Ser. No. 134,734, filed concurrently herewith (Attorneys Docket CT9-86-009). In this system, paper documents such as bank checks, are processed through a high speed reader/sorter. As the documents are processed, the magnetic ink characters on the documents are read by an MICR reader. In addition, the documents are directed past an image scanning station which electronically captures the image of both the front and back of the document.
Many kinds of documents, including bank checks, contain information in the form of sharp high contrast images, such as numbers and signatures, as well as broader, lower contrast images such as endorsements, printed inforaation, pictures, background designs and the like. Documents of this type cannot adequately be represented by black and white image data, since the thresholding of the image data into discrete black and white values results in loss of low contrast information. A high quality, high resolution gray scale image representation would adequately reproduce both high contrast images and lower contrast images, but would require massive amounts of data storage, which would be impractical and economically infeasible in a system that processes image data for high volumes of documents.